<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<video id="video" controls width="450">
			<source src="https://www.runoob.com/try/demo_source/mov_bbb.mp4" type="video/mp4"/>
		</video>
		
		<div>
			<button onclick="play()">播放/暂停</button>
			<button onclick="amplify()">放大</button>
			<button onclick="reduce()">缩小</button>
			<button onclick="normal()">普通</button>
		</div>
		<script>
			var video = document.getElementById("video");
			
			var isPlay = false;
			function play(){
				if(isPlay) video.pause();
				else video.play();
				isPlay = !isPlay;
			}
			
			function amplify(){
				video.width = "550"
			}
			
			function reduce(){
				video.width = "350"
			}
			
			function normal(){
				video.width = "450"
			}
		</script>
	</body>
</html>